Contact information

International ThermoWood Association

Snellmaninkatu 13
FIN-00170 Helsinki

(replace (at) with @)

Tel. +358 400 802 896


This is a ThermoWood® logo type used by the International ThermoWood Association

The logo is also used as a quality control stamp

Visitors since 1st Feb 2013

Visits on website:281894 pcs

ThermoWood® CONCEPT

ThermoWood® Concept is an entirety that ensures the technical and ecological quality of products sold under the trademark ThermoWood®. Development of the Concept is part of the long term plan of the Finnish ThermoWood Association to enhance use of thermally modified timber.

ThermoWood® Concept consists of the following sectors:

1. Patented thermal modification process
2. Registered trademark
3. Audited quality control system
4. Life cycle assessment (LCA)
5. Certified raw material
6. Standardisation
7. Continuous research and development activities


1. Patented thermal modification process

The industry scale ThermoWood® process was developed and patented by VTT Technical Research Centre of Finland. The patent is administrated by a company called Licentia Oy and it is valid in Austria, Belgium, Switzerland, Germany, Denmark, Spain, France, UK, Greece, Ireland, Italy, Holland, Portugal, Sweden, Japan, Canada and the USA. The license agreement for exploitation of the patent was signed by the Finnish ThermoWood Association and Licentia Oy.

Valid patents:

            JP 3585492
            US 5,678,324
            CA 2,162,374

2. Registered trademark

ThermoWood® trademark is owned by the Finnish ThermoWood Association. The trademark is now registered in EU, Switzerland, Japan and Canada.  An additional trademark registered in the EU is ThermoHout®.  Only the member companies of the Finnish ThermoWood Association have the right to use these registered trademarks.

Registered trademarks:
            ThermoWood®           EU trademark number 000922765
            ThermoHout®             EU trademark number 004296331

3. Audited quality control system

The quality control of ThermoWood® production was developed in cooperation with Inspecta Oy. Inspecta Oy is also the third party auditor of the quality control system and issues the right to use an SFS inspection mark. All member companies that produce thermally modified timber participated in the preparation of quality control.

The list of ThermoWood® producers that have the right to use the SFS inspection mark can be found at

The members that have the right to use SFS inspection mark with ThermoWood® product have also the right to use the quality stamp of the Finnish ThermoWood Association.

Some ThermoWood® producers have the right to use the KOMO certificate of the Dutch testing company SKH.

4. Life cycle assessment (LCA)

Life cycle assessment of ThermoWood® is finished.  The LCA was carried out by the Imperial College London. Abstract of ThermoWood® LCA will be published on the website of the Finnish ThermoWood Association in the near future.

5. Certified raw material

The FFCS (Finnish Forest Certification System) was developed for Finnish circumstances and it demonstrates reliably how the Finnish certified forests are managed and used. The certification system includes all the essential components for forest certification: requirements for forest management and use and chain of custody verification as well as the qualification criteria for external auditing. The FFCS was accepted by PEFC (Programme for the Endorsement of Forest Certification schemes) forest certification system. The Finnish Forest Certification Council issues the PEFC logo use rights in Finland on the behalf of the PEFC Council. About 90% of sawn wood that is thermally modified in Finland comes from PEFC certified forests.

Information about FFCS and PEFC forest certification systems can be found at

6. Standardisation

ThermoWood® product classification was completed in 2003. Two standard treatment classes were introduced. The classes are called Thermo-S and Thermo-D. Information about ThermoWood® classification can be found in the ThermoWood® handbook, ThermoWood® brochures and website of the Finnish ThermoWood Association.

Preparation of CEN standard of thermally modified timber is now in formal vote stage. At first the standard status will be Technical Specification. Preparation of the standard has been carried out by CEN/TC 175.


7. Continuous research and development activities


Finnish ThermoWood Association annually allocates resources for topical R&D activities.